Electrically-operated pump



Oct. 5, A1925. 1,602,054

Ay C. STEWART ELECTRICALIJY OPERATED PUMP Filed AugusftI 6, 1923Patented Oct. 5, 1926,

, UNITED STATES 1,602,054 PATENT OFFICE.

.ALFRED C. STEWART, 0F PASDENA, CALIFOIR'NIA..

LncTnIcALLY-ornaarnn PUMP. l

. .Application led August 6, 1923. Serial No. 656,137.

This invention relates to a pump adapted for operation by alternatingelectric current and the main object of the invention is to provide apump of this character with means whereby the alternating current is socontrolled as to ensure more eective operation of the pump and to avoidcertain diiculties arising from the ra id alternation of: the electricalcurrent in t e operating means for the pump. S

A further object of the invention is to provide in a pump of thischaracter iinproved means for elastically supporting the operatingmember of the pump to synchronize or time the samewith the alternatingcurrent.

The accompanying drawing illustrates an embodiment of my invention andreferring thereto:

Fig. 1 is a partly sectional side elevation of Ia pump showing automaticcircuit controlling means in connection therewith for controlling thealternating-.current as hereinafter described.

Fig. 2 is a section on line 2-2 in Fig. 1.

The pump shown in the drawing may comprise a casing formed with acylinder 1 in which is adapted to operate a piston 2, suit able inletand outlet valves being provided for control of the admission andexhaust of the fluid, gas, or vapor, which is to be pumped or`compressed. Said outlet valve may consist of a valve disk 3 mounted atthe top of cylinder 2 and adapted to close by gravity and control theilow of the compressed medium to an outlet connection 4.

The piston 2 may be adapted to move below the bottom of cylinder 1 inits down stroke so as to open communication to inlet 7 through which theluid, gas, or vapor to be pumped is supplied to the interior of thecasing. .l

The casing of the apparatus further comrises a downward extension 8 fromthe cylinder portion 1, said extension beingl connected at its lower endto a casing member 10, forming a field member for an electromagneticsolenoid coil or windin v11 which is surrounded or enclosed by saicasing 10,

and is adapted to cooperate with a core mein-` ber 12 of magneticmaterial which is adapted/to reciprocate within said solenoid 'coil -orwinding. vThe top of the casing 10l may have a downward extension 13 ofmagnetic material projecting within the solenoid coil or winding 11 toreduce the reluctance of the magnetic circuit. vSolenoidcore 12 is ofsuitable magnetic material, for example, soft iron, preferably laminatedor cut to minimize eddy loss and is attached to rod 14 which isconnected to the piston 2 aforesaid, so as to cause operation of' saidpiston by the reciprocation of said rod. Casing 10 may be provided witha downward extension 15 for receiving the core 12 when in lowermostposition. The cylinder 1 may be closed at lts upper end by a cap member16 and the several casing parts 1, 16, 8, 10, and 15, are tightlyconnected or joined in such a Inanner as to provide a gas tightenclosure for the operating parts, including the piston 2 and theoperating core 12.

Means are provided for elastically or resiliently mounting reciprocatingmember or unit comprising piston 2 and core 12, said 7 means preferablycomprising a flexible tiemember 17 consisting for example of a wire,band, cable, or chain which' passes through a transverse opening 18 inthe rod 14 aforesaid so as to be connected to and to extend transverselyof the reciprocating unit, and is connected at either end to a springsupported member 19 adapted to slide in a tubular radial extension 20from the casing body 8, a spring 21 being interposed between said member19 and a shoulder 22 at the inner end of said tubular radial extensionin such a manner that the flexible member 17 is held taut by theoperation of said spring means 21. The connection of tie-means 17 tospring supported member 19 is by means of a screw 24 which screws inmember 19- so as to adjust the tension of tie-means 17. The radialtubular extension 20 is closed by cap or plug 23 at its outer endforming a gastight enclosure therefor.

The solenoid coil or winding l11 is connected to a source of alternatingelectric ating solenoid coil or winding in one direction onlyand to cutoi current impulses `l05 or wave portions in the opposite direction. Forthis purpose any suitable circuit interrupter operated in synchronismwith the al ternating current may be used for example, as shownin Fig.1, -I may provide a polarvized electro-magnetic circuit controllercomprising a permanent magnet 28, andan armature 29 having its windingconnected in a shunt circuit indicated at and 31 to the wires 33 and 32of an alternating current supply circuit. A. circuit controlling arm 34may be connected to the armature 29 and is connected by wire 35 with thewire 32 of the said supply circuit and a fixed contact 36 may beprovided, adapted to cooperate with the said circuit controlling arm 34to close the circuit during those halfwaves of the alternating currentwhich it is desired to transmit to the operating solenoid, said contact36 being connected to a wire 37 leading to solenoid coil 11 and theother wire 33 of the supply circuit being connected to the other end ofsolenoid 11. The above described intermittent operation f the circuitcontrolling arm 34 is caused by the fact that armature 29 together withSaid circuit controlling arm is caused to swing to the left in Fig. 1 soas to make contactwith contact 36 upon passage of the current impulsesin one direction and to swing to the right so as to break such contactupon passage of the current impulses in the other direction. Currentcontrolling arm is sufficiently elastic to provide for maintenance ofcontactl during substantially p a half Wave period. Connection istherefore made between circuit controller 34 and contact 36 duringalternate half waves of the current so that the current impulsessupplied to the solenoid are always in the same direction and are of adefinite frequency corresponding to the frequency of the alternatingcurrent. The electric circuit connections enter the casing-10 throughgas-tight bushings 38.

The operation is as follows:

Alternating current of suitable potential difference supplied to thewires 32 and 33 I is controlled by theI operation of theelectro-magnetic circuit closer above described so that alternate waveportions corresponding to the current impulses in the same direction,and representing an intermittent unidirectional current, passes throughthe wires 25 and 26 to the solenoid 11 so that said winding isalternately energized and de-energized. During the periods ofenergization of said winding the solenoid core 12 is drawn upwardlyWithin the vwinding and the resulting upward movement of the piston 2causes compression of the gas or vapor within the piston cylinder 1.During tlie ensuingY half-wave period while the solenoid coil 11 isdeenergized core 12 is returned to normal position by operation ofgravity and of the spring means aforesaid. By the operation of the coreas above described the fluid is puin ed from the inlet 7 to the outlet4. In or er to ensure a full stroke of the reciprocating unit and toprovide for maximum efficiency of operation the resilient support forthe reciprocating unit is tensioned by adjust-ment of each adjustingdevice 24 so as to so proportion the restoring force due to the tensionof the springs 21 to the mass of the reciprocating unit that the naturalperiod of oscillation of the said reciprocating unit corresponds to theperiod of alternation of the energizing current, or more properly theperiod between successive wave impulses of the intermittent currentproduced by operation of the circuit closer on the alternating currentsupplied thereto.

It should be noted that, as shown in Fig. 1, the position of theresiliently supported flexible member 17 with respect to the motion ofthe piston 2 is such as to tend to hold said piston in a position at anintermediate point of its stroke and to resiliently resistthe movementof the piston in either direction from such position. Thile the pistonis alternately drawn upward and downward by the solenoid coil and theforce of gravity respectively, the tension means 17 resiliently resistsits motion in each direction. By reason of this fact such tension meansare particularly effective in tending to give the reciprocating member anatural period of oscillation, and by suitable adjustment of screws 24the resisting force of the springs 21 may be made such as to make thisnatural period equal to the period be tween successive current impulses.

The several casing members 1, 16, 8, 23, 10, and 15 are preferably allin tightl connection and closed so as to form a gastight enclosure forthe pump and the operating means therefor. As so constructed the deviceis applicable with especial advantage in the compression of condensablevapors as a part of a refrigerating system. In using the above describedpump 1n a refrigerating apparatus the inlet and the outlet valves of thepump are connected in the refrigerating line in the usual manner ofrefrigerating plants using a volatile liquid or readily condensablevapor, such as rhigolene, sulfur dioxide, etc., the 'function of thepump being to compress the expanded vapor so that on subsequent cooling1t will condense to li uid form and can be re-expanded to per crm therefrigerating operation. Inasmuch as there are no stuing boxes oroutside cpnnections for operating the pum yall of the working partsbeing containe within the gas tight or hermetically sealed casin thereis no leakage of the refrigerating medium from the pump into the outerair. This is an important advantage especially in the smallerrefrigerating units as such units have to be operated with a minimum ofcare and attention and it is highly desirable that the supplyv theatpparatus as described without. depart ing rom my invention, forexample, the core member which operates the piston may be so arrangedrelative to its operating solenoid as to be drawn downwardly by theaction of the solenoid and raised by the action of the spring. rlhischange in operation of the device may be brought about by inverting thedevice shown in the drawing or by suitably modifying the position of thecore with relation to the solenoid coil. Furthermore the devicedescribed may be used in any angular position either horizontal orvertical.

IVhat I claim is:

1. An electrically operated pump comprising a cylinder, a piston Workingtherein, a core in connection with said piston and forming therewith a.reciprocating unit, resilient means connected to said reciprocating unitand tending to hold the same in an intermediate position and toresiliently resist its movement in either direction from such position,4a solenoid coil in position to cause, upon energization, movement ofsaid reciprocating unit inone direction from such intermediate position,means for moving said reciprocating unit in the other direction fromsuch intermediate position uplon de-energization of said coil, means forsupplying intermittent unidirectional current impulses of definitefrequency to said solenoid coil to energize the same, and means foradjust-ing said resilient means so as to ycause the reciprocating unitin its resulting' alternate motion in opposite directions from saidintermediate position to have a natural frequency of oscillation equalto the frequency of such current impulses.

2. An electrically operated pump comprising a casing provided with acylinder, a piston Working in said casing, a. core of magnetic materialin connection with said piston and forming therewith a reciprocatingunit, a solenoid adapted to operate said core, means for supplyingintermittent unidirectional current impulses to said solenoid, wherebysaid reciprocating unit is caused to reciprocate, and spring supportingmeans in connection with said core comprising a flexible memberconnectedto and extending transversely of said reciprocating unit andspring means for tensioning said fiexible member. i

3. A construction as set forth in claim 2 and comprising in additionmeans for adjusting the spring tension on said fiexible means. Y

In testimony whereof I have hereunto sub scribed my name this 24th dayof July,

' ALFRED C. STEWART.

